1. Field of the Invention
The present invention relates to managing application features.
2. Description of Prior Art
Information services and data processing industries in general have rapidly expanded as a result of the need for computer systems to manage and store large amounts of data. As an example, financial service companies such as banks, mutual fund companies and the like now, more than ever before, require access to many hundreds of gigabytes or even terabytes of data and files stored in high capacity data storage systems. Other types of service companies have similar needs for data storage.
Data storage system developers have responded to the increased need for storage by integrating high capacity data storage systems, data communications devices (e.g., switches), and computer systems (e.g., host computers or servers) into so-called “storage networks” or “Storage Area Networks” (SANs.)
In general, a storage area network is a collection of data storage systems that are networked together via a switching fabric to a number of host computer systems operating as servers. The host computers access data stored in the data storage systems (of a respective storage area network) on behalf of client computers that request data from the data storage systems. For example, according to conventional applications, upon receiving a storage access request, a respective host computer in the storage area network accesses a large repository of storage through the switching fabric of the storage area network on behalf of the requesting client. Thus, via the host computer (e.g., server), a client has access to the shared storage system through the host computer. In many applications, storage area networks support hi-speed acquisitions of data so that the host servers are able to promptly retrieve and store data from the data storage system.
Conventional storage area network management applications typically include a graphical user interface (GUI) that enables a network manager to graphically manage, control, and configure various types of hardware and software resources associated with a corresponding managed storage area network. For example, one conventional storage management application generates a graphical user interface utilized by a storage administrator to graphically select, interact with, and manage local or remote devices and software processes associated with the storage area network. Based on use of the graphical user interface in combination with an input device such as a hand operated mouse and corresponding pointer displayed on a viewing screen or other display, a storage administrator is able to manage hardware and software entities such as file systems, databases, storage devices, volumes, peripherals, network data communications devices, etc., associated with the storage area network. Consequently, a storage management station and associated management software enables a storage administrator (a person responsible for managing the storage network) to manage the storage area network and its resources.
With respect to ways of handling such management, people today use the World Wide Web for a variety of different and diverse tasks for example locating information, ordering and buying goods on-line and managing their finances. Many users expect that these applications will operate regardless of what type of computer platform is used.
Java technology, which is a trademark of Sun Microsystems, Inc, helps provide a solution by allowing the creation of computer platform independent programs. The Java technology includes an object orientated programming language and a platform on which to run the Java applications. Java is both a compiled and an interpreted language. The source code that has been written by the application developer is compiled into an intermediate form called a Java bytecode, which is a platform independent language. At a client machine, the Java bytecodes are interpreted by the Java platform and the Java interpreter parses and runs each Java bytecode instruction on the computer. (If the Java bytecode is run as an applet which is described below, it may first be sent over the network to the client machine.)
The Java platform includes the Application Programming Interface (API), which is a large collection of ready-made software components, which provide a variety of capabilities, and the Java Virtual Machine (JVM) which will be explained in the paragraph below. Together the JVM and the API sit on top of the hardware based computer platform and provide a layer of abstraction between the Java program and the underlying hardware.
The JVM is made up of software, which can run a Java program on a specific computer platform of a client machine. Before a Java program can be run on a JVM, the Java program must first be translated into a format that the JVM recognizes, which is called a Java class file format. The Java class file format contains all the information needed by a Java runtime system to define a single Java class.
A Java applet is a small program that can be sent along with a Web page to a user that can perform interactive animations, immediate calculations, or other tasks without having to send a user request back to the server. As an example, as shown in FIG. 1, a distributed computer system 100 includes a client computer 102 that is coupled to a server (host) computer 104. The computer 102 includes a browser application 106 that, in turn, includes a requested Web page 108 having an applet 110 embedded therein capable of performing various tasks. In most situations, the applet 110 is executed by a JVM 112 that in this example is also resident in the browser 106.
In order for the JVM 112 to execute the applet 110, the applet's requisite component files (including class files, images and sounds) represented by files 114-118 must be downloaded from the server 104 to the JVM 112. Typically the server 104 is part of a distributed network of computers, such as the Internet, or in some cases could be part of an intranet type of arrangement. In any case, the files 114-118 that are required for the JVM 112 to run the applet 110 include Java class files as well as resource files that are used to support the execution of the applet 110. Such class files, includes a main class file, main.class 114, that is used by the JVM 112 as an entry point for execution of the applet 110. The server 104 also stores other class files such as b.class 116 that are used by the JVM 112 in the furtherance of executing the applet 110. Various image and sound components used in the execution of the applet 110 are stored in resource files such as c.image 118.
In order for the JVM 112 to execute the applet 110, it may be required to download some of the class and resource files as needed. This is typically accomplished by sending a file request that takes the form of an http request to the server 104 which responds by providing an http response that includes the URL of the requested file. By way of example, the JVM 112 issues a request to retrieve the main class file main.class 114 to which the server 104 responds by sending (i.e., downloading) the requested file (i.e., main.class 114). This request/response procedure is followed for every file for which the JVM 112 requires to execute the applet 110.
This arrangement is satisfactory for executing most small applets on small, local networks. However as the complexity of the applet increases (thereby increasing both the size and the number of requested files), the performance of the JVM 112 may be substantially degraded since the time required to satisfy the increasingly voluminous requests for the increasingly larger files in an increasingly more complex network of computers becomes greater.
With the introduction of what is referred to as a Java Archive (JAR) file, the performance of network Java applications, such as applets, is somewhat improved. A JAR file has a platform-independent file format that aggregates many files into one. In those applications using JAR files, multiple Java applets and their requisite components (.class files, images and sounds, etc.) can be bundled in a JAR file and subsequently downloaded to a browser in a single HTTP transaction thereby greatly improving the download speed. In addition, the JAR format also supports compression, which reduces the file size, further improving the download time. For example, referring to FIG. 2, the applet component files 114-118 are stored in a single JAR file 120. Using this arrangement, in order for the JVM 112 to execute the applet 110, only a single HTTP file request 122 is required to download the compressed JAR file 120 that contains all the applet component files 114-118.
A Java.net.URLClassLoader (“URLClassLoader”) class loader may be used for loading classes and resources that are accessed by searching a set of URLs. The URLs can refer either to directories or to JAR files.
A JAR file can define a hierarchical structure that includes one or more folders that include files. In this case, when the files are subsequently extracted for access, the folders are created and the files are placed in the appropriate folders.